POLYMERIC MICROCAPSULES OF THE HERBICIDES ATRAZINE AND METRIBUZIN - PREPARATION AND EVALUATION OF CONTROLLED-RELEASE PROPERTIES

Atrazine and metribuzin were microencapsulated within 5 different poly mers by the solvent evaporation process using two different emulsifier s (for a total of 20 formulations). Herbicide efficacy studies on Flor ida beggarweed, smallflower morningglory, tall morningglory, and Palme r amaranth were conducted in the greenhouse. Nine of the 10 atrazine f ormulations were at least as effective as a commercial dry flowable fo rmulation, and 5 exhibited superior herbicidal activity and controlled -release properties for over 32 weeks after treatment. The polymers de monstrating the most efficacy were cellulose acetate butyrate and ethy lcellulose. Five of the 10 metribuzin formulations had activities comp arable to or slightly less than the commercial formulation and exhibit ed controlled-release properties; the other 5 had moderate to low herb icidal activity.